An SSD (Solid State Drive) is a type of data storage device that uses NAND-based flash memory to store data persistently. Unlike traditional hard disk drives (HDD) that use spinning disks to store data, SSDs have no moving parts, which makes them faster, more reliable, and more durable. They are commonly used in computers to store the operating system, applications, and other data, and offer faster boot times, shorter application load times, and improved overall system performance compared to HDDs. Additionally, SSDs consume less power, produce less heat, and are lighter in weight compared to HDDs.